POWER EFFICIENT SOFTWARE RECEIVER FOR SPREAD SPECTRUM SIGNALS

• US 20090010308A1
• Filed: 09/29/2005
• Published: 01/08/2009
• Est. Priority Date: 09/29/2005
• Status: Active Grant

• Current Assignee: Qualcomm technologies international, ltd. (Qualcomm, Inc.)
• Original Assignee: Nordnav Technologies AB (Qualcomm, Inc.)
• Inventors: Normark, Per-Ludvig, Stahlberg, Christian
• Granted Patent: US 8,428,097 B2
• Time in Patent Office: Days
• US Class Current: 375/130
• CPC Class Codes: G01S 19/34 Power consumption
• CPC Class Codes: G01S 19/37 Hardware or software details of the signal processing chain

Abstract

The present invention relates to reception and processing of spread spectrum signals to produce position/time related data. A proposed receiver includes a radio signal processing unit, which is at least partly implemented in software running on a microprocessor. The processor is also adapted to effect at least one separate software-controlled function. The receiver is adapted to operate the radio signal processing unit on at least two processing intensity levels each with different processing times. Thereby, when the radio signal processing unit operates on a low processing intensity level, a first amount of processing capacity is available for the at least one separate software-controlled function; and when the radio processing unit operates on a high processing intensity level, a second amount of processing capacity is available for the at least one separate software-controlled function. When the processor'"'"'s over-all processing capacity is constant, the second amount is smaller than the first amount.

Claims

1. A spread spectrum signal receiver adapted to receive a number of radio signals (S_HF), the receiver comprising a radio signal processing unit (115) adapted to produce position/time related data (D_PT) in response to the received signals (S_HF), the receiver being adapted to operate the radio signal processing unit (115) on at least two processing intensity levels (OFF, STDB, TR, ACQ) each at which an amount of processing per time unit (PI) is different, characterized in that

the radio signal processing unit (115) is at least partly implemented in a software (115s) running on a microprocessor (110), the microprocessor (110) is adapted to effect at least one separate software-controlled function (117) in addition to the at least-part implementation of the radio signal processing unit (115), such that

during periods when the radio signal processing unit (115) operates on a relatively low processing intensity level (OFF, STDB), a first amount of processing capacity is available for the at least one separate software-controlled function (117), and

during periods when the radio processing unit (115) operates on a relatively high processing intensity level (TR, ACQ), a second amount of processing capacity is available for the at least one separate software-controlled function (117), the second amount being smaller than the first amount.

2. The receiver according to claim 1, characterized in that the radio signal processing unit (115) is entirely implemented in the software (115s) which runs on the microprocessor (110).

3. The receiver according to any one of the preceding claims, characterized in that the receiver is adapted to operate in at least two operation modes, and for each operation mode a unique operation scheme (OS_HP, OS_LA, OS_PF) is defined according to which the processing performed by the radio signal processing unit (115) is distributed over time between the at least two processing intensity levels (OFF, STDB, TR, ACQ).

4. The receiver according to claim 3, characterized in that the at least two processing intensity levels (OFF, STDB, TR, ACQ) comprise a signal-source-acquisition level (ACQ) at which the radio signal processing unit (115) is adapted to operate when searching for, identifying and synchronizing with at least one radio signal source.

5. The receiver according to claim 4, characterized in that the radio signal processing unit (115) is adapted to operate on the signal-source-acquisition level (ACQ) when generating a first estimate of the position/time related data (D_PT).

6. The receiver according to any one of the claims 3 to 5, characterized in that the at least two processing intensity levels (OFF, STDB, TR, ACQ) comprise a tracking level (TR) at which the radio signal processing unit (115) is adapted to operate when (t_TR) receiving signals (S_HF) from a number of identified radio signal sources, and based thereon repeatedly producing updates of the position/time related data (D_PT).

7. The receiver according to any one of the claims 3 to 6, characterized in that the at least two processing intensity levels (OFF, STDB, TR, ACQ) comprise a stand-by level (STDB) at which the radio signal processing unit (115) is adapted to operate during a stand-by interval (t_STDB) while maintaining a predefined synchronicity accuracy with at least one previously identified radio signal source.

8. The receiver according to claim 7, characterized in that, when the radio signal processing unit (115) operates on the stand-by level (STDB), the receiver is adapted to receive a signal (S_HF) from at most one identified radio signal source.

9. The spread spectrum signal receiver according to any one of the claims 3 to 8, characterized in that the at least two processing intensity levels (OFF, STDB, TR, ACQ) comprise a power-off level (OFF) at which the radio signal processing unit (115) is adapted to operate in a manner which avoids processing of any radio signals.

10. The receiver according to claim 9, characterized in that the receiver comprises:

a radio front-end module (130) adapted to receive the radio signals (S_HF) and perform sampling and digitizing (S_BP) thereof, and

a system clock unit (150) adapted to deliver a clock signal (CL) to each of the radio signal processing unit (115) and the radio front-end module (130), and

when the radio signal-processing unit (115) operates on the power-off level (OFF), the receiver is adapted to inhibit (c₁) the clock signal (CL) to the radio front-end module (130).

11. The receiver according to any one of the claims 9 or 10, characterized in that the receiver comprises:

a radio front-end module (130) adapted to receive the radio signals (S_HF) and perform sampling and digitizing (S_BP) thereof, and when the radio signal-processing unit (115) operates on the power-off level (OFF), the receiver is adapted to inhibit a power supply to the radio front-end module (130).

12. The receiver according to any one of the claims 3 to 11, characterized in that the at least two operation modes comprise a high performance mode for which the operation scheme (OS_HP) defines:

an initial signal-source-acquisition level (ACQ) operation for the radio signal processing unit (115), and

a subsequent tracking-level (TR) operation for the radio signal processing unit (115).

13. The receiver according to any one of the claims 3 to 12, characterized in that the at least two operation modes comprise a location-awareness mode for which the operation scheme (OS_LA) defines:

an initial signal-source-acquisition level (ACQ) operation for the radio signal processing unit (115), and

a subsequent phase during which the radio signal processing unit (115) is controlled to alternately operate on the tracking level (TR) and the stand-by level (STDB).

14. The receiver according to claim 13, characterized in that the receiver comprises at least one interface (160, 170) adapted to receive at least one control signal (MODE_ctrl;

USER_ctrl) influencing at least one of;

a time ratio of operation on the tracking level (TR) and the stand-by level (STDB) respectively,

time instances (t2, t4) at which the radio signal processing unit (115) is controlled to operate on the tracking level (TR), and time instances (t3, t5) at which the radio signal processing unit (115) is controlled to operate on the stand-by level (STDB).

15. The receiver according to any one of the claims 4 to 14, characterized in that receiver comprises a user interface (170) adapted to receive user-initiated measurement control commands (USER_ctrl), the at least two operation modes comprise a push-to-fix mode for which the operation scheme (OS_PF), after reception of a user-initiated measurement control command (USER_ctrl), defines:

an initial signal-source-acquisition level (ACQ) operation for the radio signal processing unit (115), and

a subsequent tracking-level operation (TR) for the radio signal processing unit (115) during at least a predefined measurement period.

16. The receiver according to claim 15, characterized in that the receiver is adapted to, after expiry of the predefined measurement period, control the radio signal processing unit (115) to operate on the power-off level (OFF).

17. A method of operating a spread spectrum signal receiver, the receiver being adapted to receive a number of radio signals (S_HF) and based thereon derive position/time related data (D_PT), and a radio signal processing unit (115) of the receiver being at least partly implemented in a software (115s) running on a micro-processor (110) which is adapted to effect at least one separate software-controlled function (117) in addition to the at least-part implementation of the radio signal processing unit (115), the method comprising controlling the radio signal processing unit (115) to operate on one of at least two processing intensity levels (OFF, STDB, TR, ACQ) each at which an amount of processing per time unit (PI) is different, rendering

a first amount of processing capacity available for the at least one separate software-controlled function (117) during periods when the radio signal processing unit (115) operates on a relatively low processing intensity level (OFF, STDB), and

a second amount of processing capacity available for the at least one separate software-controlled function (117) during periods when the radio processing unit (115) operates on a relatively high processing intensity level (TR, ACQ), the first amount being larger than the second amount.

18. The method according to claim 17, characterized by the radio signal processing unit (115) being entirely implemented in the software (115s) which runs on the microprocessor (110).

19. The method according to any one of the claims 17 or 18, characterized by controlling the receiver to operate in one of at least two operation modes, each mode being associated with a unique operation scheme (OS_HP, OS_LA, OS_PF) which defines a distribution over time of the processing performed by the radio signal processing unit (115) between the at least two processing intensity levels (OFF, STDB, TR, ACQ).

20. The method according to claim 19, characterized by the at least two processing intensity levels (OFF, STDB, TR, ACQ) comprising a signal-source-acquisition level (ACQ) at which the radio signal processing unit (115) is adapted to operate when searching for, identifying and synchronizing with at least one radio signal source.

21. The method according to claim 20, characterized by the radio processing unit (115) being adapted to operate on the signal-source-acquisition level (ACQ) when generating a first estimate of the position/time related data (D_PT).

22. The method according to any one of the claims 19 to 21, characterized by the at least two processing intensity levels (OFF, STDB, TR, ACQ) comprising a tracking level (TR) at which the radio signal processing unit (115) is adapted to operate when receiving signals from a number of identified radio signal sources, and based thereon repeatedly producing updatings of the position/time related data (D_PT).

23. The method according to any one of the claims 19 to 22, characterized by the at least two processing intensity levels (OFF, STDB, TR, ACQ) comprising a stand-by level (STDB) at which the radio signal processing unit (115) is controlled to operate during a stand-by interval (t_STDB) while maintaining a predefined synchronicity accuracy with at least one previously identified radio signal source.

24. The method according to claim 23, characterized by, during the stand-by interval (t_STDB):

controlling the radio signal processing unit (115) to operate on the stand-by level (STDB), and

controlling the receiver to receive a signal (S_HF) from at most one identified radio signal source.

25. The method according to any one of the claims 19 to 24, characterized by the at least two processing intensity levels (OFF, STDB, TR, ACQ) comprising a power-off level (OFF) at which the radio signal processing unit (115) is controlled to avoid processing of any radio signals.

26. The method according to any one of the claims 19 to 25, characterized by the at least two operation modes comprising a high performance mode for which the operation scheme (OS_HP) defines:

an initial signal-source-acquisition-level (ACQ) operation for the radio signal processing unit (115), and a subsequent tracking-level (TR) operation for the radio signal processing unit (115).

27. The method according to any one of the claims 19 to 26, characterized by the at least two operation modes comprising a location-awareness mode for which the operation scheme (OS_LA) defines:

an initial signal-source-acquisition-level (ACQ) operation for the radio signal processing unit (115), and a subsequent phase during which the radio signal processing unit (115) is controlled to alternately operate on the tracking level (TR) and the stand-by level (STDB).

28. The method according to claim 27, characterized by receiving at least one control signal (MODE_ctrl, USER_ctrl) influencing at least one of:

a time ratio of operation on the tracking level (TR) and the stand-by level (STDB) respectively,

time instances (t2, t4) at which the radio signal processing unit (115) is controlled to operate on the tracking level (TR), and

time instances (t3, t5) at which the radio signal processing unit (115) is controlled to operate on the stand-by level (STDB).

29. The method according to any one of the claims 19 to 28, characterized by the at least two operation modes comprising a push-to-fix mode for which the operation scheme (OS_PF), after reception of a user-initiated measurement control command (USER_ctrl), defines:

an initial signal-source-acquisition level (ACQ) on which the radio signal processing unit (115) is controlled to operate, and

a subsequent tracking-level (TR) operation on which the radio signal processing unit (115) is controlled to operate during at least a predefined measurement period.

30. The method according to claim 29, characterized by, after expiry of the predefined measurement period, the method comprising controlling the radio signal processing unit (115) to operate on the power-off level (OFF).

31. A computer program directly loadable into the internal memory of a computer, comprising software for controlling the steps of any of the claims 17 to 30 when the program is run on the computer.

32. A computer readable medium (180), having a program recorded thereon, where the program is to make a computer control the steps of any of the claims 17 to 30.